General timeline
The world of the Endless Ocean is largely defined by a particular series of events, most of which revolve around the Architects. To understand many of the peculiarities of the world, one must first understand this series of events. ---- The Architects came to the Endless Ocean from somewhere else, though only they know where. When they arrived, they found that there were peoples who had existed there for far longer. There were the plentiful Mora, the industrious Xians, and the physically powerful Krek, along with countless beasts and monsters. Curious about this new world and its inhabitants, the Architects inadvertently triggered a catastrophe known as the First Shattering while studying a peculiar metal called Derrite, tearing the lands of the Endless Ocean asunder and irrecoverably altering the world (resulting in the three continents of Ragna, Voy, and Tor as well as the countless smaller islands). Ashamed of what they had done and unwilling to meddle with the world any more than they already had, the Architects lifted one of the broken continents into the sky with their powerful magic and imbued it with a powerful Great Spirit, creating for themselves both a sanctuary and a place to study the world they had found themselves in without interfering with the majority of it. Seeking to learn from the natives of what was now the sky-continent of Atanui the Architects took it upon themselves to become benevolent protectors. Over time, the bloodlines and cultures mixed, and the magic of the Architects seeped into the people of Atanui along with the knowledge of how to create some of their enchantments. The Architects' caste system was easily adopted, and the art of mask-making was passed on along with the secret of how to turn them into powerful magical artifacts. So too was the ritual required to transform someone into a Guardian, an angelic figure with great power who served as the enforcers of peace. Eventually the Architects decided that they had taught the natives enough; they withdrew into their sanctuaries, leaving the Great Spirit to watch over their charges. Things were good, for a time. But then the Architects vanished. The Brotherhood of Order (an organization of incredibly powerful Architect-blooded Xian Guardians who served as the hands of the Great Spirit) investigated this, but could find no explanation. Deciding that this was some kind of test, they stepped up and claimed the relics of the Architects for themselves and vowed to rule over Atanui until the Architects returned. But the Architects did not return. A schism formed within the Brotherhood between those who thought that their role was simply that of keeping the Architect's domain safe until they came back and those that thought they should instead use the tools of the Architects as they saw fit. The schism grew worse and worse until a terrible conflict known afterwards as the War of Ruining erupted, tearing across Atanui like a great storm despite the best efforts of the Hand of the Architects to covertly halt the fighting. In the chaos of the war, the Great Spirit was badly wounded and the enchantments keeping the sky-continent afloat above the Endless Ocean began to fail. In a cataclysm thereafter known as the Second Shattering, Atanui crumbled apart. Some portions fell from the sky, crashing into the waves or slamming into the continents below, while others remained aloft, drifting apart. In the aftermath, the people of Atanui spread across the lands of the Endless Ocean, bringing with them the culture and blood of the Architects, these traits giving them an edge that let them survive in the hostile world that they had floated above for so long.